Discriminating clamp actuating mechanism



Nbv. 26, 1935. D. c. KLAUSMEYER 2,022,355

DISCRIMINATING CLAMP ACTUATING MECHANISM Original Filed March 12, 1929 2Sheets-Sheet l DAV/D C. KLAl/JMEYER DECEAJED B) H. HENRY \Sl/NDERMANN WEXELUTOR 3 N66. 26, 193 D. c. KLAUSMEYER DISCRIMINATING CLAMP ACTUATINGMECHANISM Original Filed March 12, 1929 2 Sheets-Sheet 2 Patented Nov.26, 1935 PATENT OFFICE DISCRIMINATING CLAMP AOTUATING MECHANISM David C.Klausmeyer, deceased, late of Cincinnati,

Ohio, by H. Henry Sundermarm, executor, Cincinnati, Ohio, assignor toThe Cincinnati Bickford Tool Company, Cincinnati, Ohio, a corporation ofOhio Original application March 12, 1929, Serial No. 346,462. Dividedand this application June 7,

1932, Serial No. 615,868

3 Claims. (CI. 77-28) This application is a division of application,Serial No. 346,462, filed March 12, 1929 by David C. Klausmeyer, whichhas matured into Patent No. 1,875,017 dated August 30, 1932. 1

The present invention relates to clamping mechanisms such as may beused, for example, to clamp a movable portion of a machine tool to astationary portion thereof during a machining operation.

A primary object of the invention is to provide a power actuatedclamping mechanism in which the force capable of being transmitted tothe clamp during the clamping action will be substantially less than theforce capable of being transmitted thereto during an unclamping action,whereby the possibility of so tightly setting the clamp that it cannotbe opened by the power means is precluded.

Another object is to provide a clamping mechanism and power actuatingmeans therefor so constructed and arranged that the prime mover of saidpower actuated means may continue tooperate after the clamping orunclamping action has been completed, without injury to the clampdevice, the clamp actuating mechanism or the prime mover.

Still another object of this invention is to provide a power actuatedclamping mechanism embodying a relatively small electric motor and powermultiplying gearing intermediate the motor and the clamp means, wherebythe relatively small motor is rendered capable of transmitting arelatively great force to the clamp means.

These and other objects have been attained by the provision of a clampmechanism comprising a contractile and expansile element adapted to beactuated, to effect clamping and unclamping ac tion, by forward andreverse movements of an oscillatory shaft. Other forms of clampelements, however, may be employed. A reversible electric motor isconnected, by speed reduction gearing, preferably of the worm andworm-wheel type, with the clamp actuating shaft. The flow of current tosaid motor, to effect forward and reverse rotation of the shaft, iscontrolled by suitable manually actuable switches, preferably located ina position readily accessible to the operator of the machine tool. Meansalso is provided for rendering ineffective the driving connectionbetween the motor and the clamp when the resistance to movement hasreached a predetermined value, both in clamp closing and clamp openingmovements, without discontinuing the actuation of the prime mover.

To insure that the power means will, at all times, be capable of openingthe clamp, after having previously closed it, this invention proposes toembody in the power drive, between the motor and the clamp, adiscriminating slipclutch adapted to transmit a substantially greatertorque in clamp opening movement than in clamp closing movement.

While this invention will be shown and described as embodied in a poweractuated clamp means, it is to be understood that it is in nowiselimited to such embodiment but may also be employed, to advantage, inmanually actuable clamps.

Other objects and advantages will be in part indicated in the followingdescription and in part rendered apparent therefrom in connection withthe annexed drawings.

To enable others skilled in the art so fully to apprehend the underlyingfeatures hereof that they may. embody the same in the various wayscontemplated by this invention, drawings depicting a preferred typicalconstruction have been annexed as a part of this disclosure and, in suchdrawings, like characters of reference denote cor responding partsthroughout all the views, of whichz- Figure 1 is an elevational view ofa portion of a machine tool embodying the present improved clampactuating means. Fig. 2 is a detail sectional view on the line 22 ofFig. 1. Fig. 3 is a horizontal sectional View on the line 3-3 of Fig. 1,showing the connection between the actuating motor and the clampactuating shaft, later to be referred to. Fig. 4 is a vertical sectionon the line fil of Fig. 3 but showing, in addition, adjusting means tovary the tension on the detent elements thereby to vary the torqueadapted to be transmitted. Fig. 5 is a section substantially on the line55 of Fig. 4.

Referring more specifically to the drawings, and particularly to Figs. 1and 2, one form of the invention is disclosed as comprising acontractile and expansile clamp element I in the nature of an annularsleeve, split as at 2 and adapted to be contracted to cause its innersurface 3 to grip the outer cylindrical surface 4 of a post or column 5,thereby to lock the two elements together to prevent relative movementtherebetween. Projecting from the clamp element, at one side of thesplit 2, are ears 8 Within which is journaled a clamp actuating shaft 1.Complemental ears 8 are also formed on the clamp element i at theopposite side of said split. Intermediate the ears 6 the shaft 1 isprovided with an eccentric portion 9 surrounded by a strap l0 into whichis threaded a draw bolt H which projects through one of the ears 8 andhas its head l2 connected to the ear 8 through the medium of a bushingl3 and thrust bearing I4. It will readily be perceived that oscillationof the shaft 1 to the position shown in Fig. 2 will move the boltaxially and thereby effect contraction of the clamp element l, and thatoscillation of the shaft from that position will permit the clampelement to open due to the resiliency of the metal therein. Limit boltsl5 passing loosely through the ears 8 and threaded into the ears 6 serveto limit the expansion of the clamp element. A hand lever I5 fixed tothe draw bolt I! may be utilized to rotate said bolt, which, through itsthreaded connection with the strap it, will effect relative axialmovement between the strap 19 and the bolt-head I2 and thereby contract,or permit to expand, the clamp element I.

This invention relates primarily to the provision of power means foractuating the clamp element and to that end a suitable prime mover isconnected to effect oscillation of the shaft i. This power meanspreferably comprises a reversible electric motor M. Inasmuch as theshaft 1 requires only a partial rotation to effect a complete movementof the clamp element it has been found desirable to employ reductiongearing between the motor and the shaft whereby the motor may make asubstantial number of rotations while the clamp actuating shaft ismaking only a partial rotation. This conveniently may be effected by theuse of a worm l1 and a cooperating worm-wheel 25, the former beingconnected to the motor shaft and the latter being operatively connectedwith the shaft 1, as later will be described.

The parts are normally so adjusted that, as the eccentric approaches itsdead center position as shown in Fig. 2, the clamp element will betightly gripped upon the member 6. If for any reason, such for exampleas because of wear, the eccentric should pass through its dead centerposition without completely closing the clamp, an abutment !9, providedby a casing 20 which houses the worm if and worm-wheel 25, will engagean arm 35 fixed to the shaft 1' and prevent further rotation of theshaft I. A yielding abutment 24 is adapted to engage the arm 35 uponcomplete opening of the clamp.

When the clamp has been completely closed, or completely opened, themotor may continue to .run until the operator causes, or permits, the

circuit thereto to be broken. This continued actuation of the primemover is rendered possible by reason of the fact that the worm-wheel 25,which is engaged by the worm I1, is completely circular and is connectedwith the shaft 1 by a slip-clutch device positive in its action totransmit to said shaft a predetermined torque in each direction ofrotation and then to slip. This slip-device comprises two members A andB which are arranged, preferably in nested relation, and which arerelatively movable both in a clockwise and in a counter-clockwisedirection. One of these members may be utilized as a driver and theother as a follower. In the arrangement shown the female member A issecured upon the worm-gear 25 and serves to drive the male member B,which is keyed to the shaft 1. The member B is provided with a series ofradial perforations 26 in which are located a series of detents 21 whichare normally pressed radially outward by means of expansile springs 28,which are adjustable as to tension as will presently be described. Thesedetents are shown in the form of hardened balls and they normally engagean annular run-way affording two series of facets a, and b provided bythe female member A. These facets are inclined in opposite directionsand at different angles to a radial line intersecting their point ofconnection at which point the balls 2? bear, under the action of thesprings 22. The facets a are disposed at a more acute angle to a radialline than are the facets 12. Consequently it requires greater torque tocompel the balls to climb the facets 11. than to climb the facets b. Asa result of this construction the device will transmit a greater torquewithout yielding in the one direction than in the other and yet, byvirture of the fact that the balls are normally seated in the pocketsformed by the construction, the device is positive in action withincertain limits and quite devoid of any tendency to creep.

The device is so arranged that rotation of the member A in a clockwisedirection (as viewed in Fig. 3) effects a clamp closing movement of theshaft 7 and rotation in the opposite direction effects an unclampingaction. It will therefore be apparent that a substantially greatertorque will be transmitted to the shaft i to effect unclamping than toeffect clamping. This insures against the clamp being so tightly setthat the motor would be unable to release it. a

It is desirable to be able to adjust the pressure of the detent ballsagainst the raceway and, inasmuch as there is a plurality of detents, itis desirable that the tension may be adjusted uniformly so that eachwill bear the same load. This is accomplished by locating a member 29 inthe nature of a support for the inner end of each spring. The member 29may, to good advantage, be in the shape of a ball. These balls are, inturn, supported by the conical face 30 of a collar P which is slidablymounted on the periphery of the hub 3| of the male member B. The end ofthe collar enters an annular groove 32 which is cut in the outer face ofthe member B and intersects the radial perforations so as to expose theballs 29 and enable their radial positions, and thereby the tension ofthe springs 28, to be determined by axially shifting the collar P. Theposition of the collar is,'in turn, determined by a nut 33 actingthrough a washer 34; the nut being threaded to the extremity 1' of theshaft 1. By turning the nut, the tension of the detents 21 may beregulated at will.

It is to be understood that the torque transmitted from the member A tothe member B is sufficient to effect closing and opening of the clampelement l and that after the rotation of the shaft has been arrested,either by tightening of the clamp or by contact of the arm with eitherof the abutments I9 or 24 a continued rotation of the worm H by themotor M will cause the balls 2? to ride up the facets w or 1), dependentupon the direction of rotation, and the member A may continue to rotaterelative to the member B.

It will thus be seen that this invention is well adapted to accomplishthe objects enumerated in the foregoing.

Without further analysis, the foregoing will so fully reveal the gist ofthis invention that others can, by applying current knowledge, readilyadapt it for various utilizations by retaining one or more of thefeatures that, from the standpoint of the prior art, fairly constituteessential characteristics of either the generic or specific aspects ofthis invention and, therefore, such adaptations should be, and areintended to be comprehended within the meaning and range of equivalencyof the following claims:

Having thus revealed this invention, what is claimed as new and desiredto be secured in the following combinations and elements, or equivalentsthereof, by Letters Patent of United States:

1. A column clamping mechanism for a radial drill combining acontractible clamp element; a rotatable eccentric and a draw boltactuated thereby to contract said clamp element; actuating means forsaid eccentric including an oscillatory shaft adapted by rotation in onedirection to cause said eccentric to effect clamping action and byrotation in the reverse direction to effect unclamping action; areversible motor; a driving connection between said motor and saidshaft, said driving connection including an impositive coupling deviceadapted to transmit substantially greater torque in one direction ofrotation than in the reverse direction, said device comprising a memberfixed to said shaft; a second member rotated by said motor, one of saidmembers affording a first series of facets inclined in one direction andat one angle to a radial line and a second series of facets inclined inanother direction and at another angle to a radial line; and yieldingelements carried by the other member and engaging said facets.

2. In a radial drill having an upright post and a sleeve rotatablymounted thereon and provided at its lower end with a split tubularportion embracing a cylindrical portion of said post; actuating means tocontract said split tubular portion to cause it to clamp said sleeve tosaid post, and means to render said actuating means ineffective therebyto permit said split portion to expand and release said post, said meanscomprising a vertically arranged shaft journaled in bearings provided bysaid sleeve at one side of said split; an eccentric on said shaft; adraw bolt having one portion embracing said eccentric and anotherportion connected with said sleeve at the opposite and provided with twoseries of oppositely and unequally inclined facets engaged by saidelements, said facets transmitting through said elements rotarymovements to said first member and shaft; a first gear connected withsaid second member; a second gear meshing with and driving said firstgear; and a reversible electric motor connected to rotate said secondgear in forward and reverse directions. I

3. A clamping mechanism for radial drills having a post and a sleeverotatably journaled thereon comprising an oscillatory shaft and meansactuated by the rotation thereof in one direction for clamping saidsleeve to the post and by the rotation thereof in the opposite directionfor releasing said sleeve from said post; a reversible motor carried bysaid sleeve, a driving connection between said motor and said shaftincluding an impositive clutch adapted to transmit substantially greatertorque in clamp opening movement than in clamp closing movement, saidclutch device comprising a first rotatable member journaled coaxiallywith said shaft and provided with an internal annular run-way formed oftwo series of facets inclined at different angles and in oppositedirections to radial lines; a second member secured to said shaft andprovided with a plurality of spring pressed elements engaging saidfacets; a worm gear secured to said first member; a worm engaging saidworm wheel; and a driving connection between said reversible motor andsaid worm.

H. HENRY SUNDERMANN,

Executor 0 the Last Will and Testament of David C. Klausmeyer, Deceased.

